wytp.proof

Interface Proof.State

All Known Implementing Classes:

AbstractProof.AbstractState, DeltaProof.State

Enclosing interface:

Proof

public static interface Proof.State

A proof branch considered of one or more states which were derived from an existing state using a given rule.

Author:

David J. Peare

Method Summary

Modifier and Type	Method and Description
Formula	allocate(Formula f) Ensure a given formula is properly allocated into this state.
void	applyBypass(Proof.State bypass)
Proof.State	getChild(int ith) Get the child state resulting from this step
Proof.Delta	getDelta() Get the delta between this state and its parent.
Proof.Delta	getDelta(Proof.State ancestor) Get the delta between this state and an ancestor.
List<Formula>	getDependencies() Get the formulae on which this step depends
Proof.State	getParent() Get the parent (i.e.
Proof	getProof() Get the enclosing proof for this step.
Proof.Rule	getRule() Get the name of the rule used for this step.
TypeInferer.Environment	getTypeEnvironment() Get the typing environment at this state in a given proof.
Proof.State	infer(Proof.Rule rule, Formula truth, Formula... dependencies) Infer a new fact from one or more existing facts.
boolean	isKnown(Formula truth) Determine whether a truth is already known or not.
int	numberOfChildren() Get the number of child steps originating from this step
Proof.State	refine(Proof.Rule rule, WyalFile.VariableDeclaration variable, WyalFile.Type type, Formula... dependencies) Refine the type of a given variable in this state.
Proof.State[]	split(Formula.Disjunct disjunct) Apply a simple proof step which splits a given disjunct into several sub-states.
Proof.State	subsume(Proof.Rule rule, Formula truth, Formula replacement, Formula... dependencies) Subsume a given truth by a replacement.

Method Detail

getProof

Proof getProof()

Get the enclosing proof for this step. Every step must be associated with a proof, and all connected steps must be in the same proof.

Returns:

getParent

Proof.State getParent()

Get the parent (i.e. before) state for this step. This is null if this state represents the root of the proof.

Returns:

isKnown

boolean isKnown(Formula truth)

Determine whether a truth is already known or not. Truths which are already known do not need to be reintroduced.

Parameters:

truth -

Returns:

getDelta

Proof.Delta getDelta()

Get the delta between this state and its parent.

Returns:

getDelta

Proof.Delta getDelta(Proof.State ancestor)

Get the delta between this state and an ancestor.

Returns:

getRule

Proof.Rule getRule()

Get the name of the rule used for this step.

Returns:

getTypeEnvironment

TypeInferer.Environment getTypeEnvironment()

Get the typing environment at this state in a given proof. The type environment gives the current type for all declared variables. The environment is not static as the type of a given variable can be refined at any given state as more facts become known.

Returns:

getDependencies

List<Formula> getDependencies()

Get the formulae on which this step depends

Returns:

numberOfChildren

int numberOfChildren()

Get the number of child steps originating from this step

Returns:

getChild

Proof.State getChild(int ith)

Get the child state resulting from this step

Returns:

applyBypass

void applyBypass(Proof.State bypass)

split

Proof.State[] split(Formula.Disjunct disjunct)

Apply a simple proof step which splits a given disjunct into several sub-states.

Parameters:

disjunct -

Returns:

subsume

Proof.State subsume(Proof.Rule rule,
                    Formula truth,
                    Formula replacement,
                    Formula... dependencies)

Subsume a given truth by a replacement.

Parameters:

rule -

truth -

replacement -

dependencies -

Returns:

infer

Proof.State infer(Proof.Rule rule,
                  Formula truth,
                  Formula... dependencies)

Infer a new fact from one or more existing facts.

Parameters:

rule -

truth -

dependencies -

Returns:

refine

Proof.State refine(Proof.Rule rule,
                   WyalFile.VariableDeclaration variable,
                   WyalFile.Type type,
                   Formula... dependencies)

Refine the type of a given variable in this state. That is, make the type more precise at this point.

Parameters:

rule - The rule which is causing this particular refinement.

variable - The variable whose type is being refined.

type - The type which this variable is refined with.

dependencies - The immediate dependencies needed to establish this refinement.

Returns:

allocate

Formula allocate(Formula f)

Ensure a given formula is properly allocated into this state.

Parameters:

f -

Returns: